The bearing capacity of a single pile in clay is mainly due to _____

The efficiency of pile group depends upon ______

When the under-reamed pile has only one bulb, it is called _____

When a pile hammer hits the pile, the total driving energy is equal to _____

For pile in cohesive soil ______ is neglected for individual pile action.

Cast-in-situ piles may be classified in to ____ classes.

In the process of pile foundation, boring is done with the help of _____

Modern pile driving method was first invented by _______